On 2018/05/02 20:23, Dmitry Vyukov wrote: > #syz dup: INFO: rcu detected stall in blkdev_ioctl The cause of stall turned out to be ioctl(loop_fd, LOOP_CHANGE_FD, loop_fd). But we haven't explained the cause of NULL pointer dereference which can occur when raced with ioctl(LOOP_CLR_FD). Therefore, #syz undup
